this code will require the the contact-form-7 and the advanced-custom-fields-pro plugin – witch require a custom installation.

The important part is the $plugins array:

The key is the path after /wp-content/plugins/ of the plugin file.
The name should be the name of the plugin – here you are able to add a link like in the example.
The slug should be false if the required plugin is a custom one and not in the Wordpress reposetory – otherwise it should contain the slug https://wordpress.org/plugins/{SLUG}.

The functions used in the snipped should also work for WP installations lower then 4.6.1 but where not tested. The error-message could also be a bit more bling bling but I’m sure this isn’t a challenge for anyone of you if you are searching for codes like this 😉

Developed for

USE AT YOUR OWN RISK

WordPress 4.6.1 tested

As first lines of code inside functions.php of a custom or child theme

Should also work in any plugin

up to 11

It seems like there will be an new Plugin directory https://wordpress.org/plugins-wp/ as soon as the switch will happen this snippet should get an update.

The function could also be used to get the requirement status e.g. inside the rendering of the page – just use it as